As Trump and Kanye show, a rich enough person feels confident saying anything–even with no evidence. So it’s fitting that Amazon founder Jeff Bezos, the richest person in the solar system (with about $148 billion), has said the craziest thing about space. He told Wired, in a new article and at the magazine’s 25th Annual Wired Summit, that off-world habitats could house, “millions, billions, maybe even a trillion people.”

“We are starting to bump up against the absolute true fact that Earth is finite,” Bezos said–which is correct. Also correct: The resources beyond Earth are really finite. Mars (Elon Musk’s top real estate venture) scarcely has any water or atmosphere, compared to Earth, but plenty of killer radiation. Earth’s moon is worse. (A new study indicates spending much time beyond Earth’s protective magnetic field could entail fatal radiation doses.)

Bezos is a devotee of his former Princeton professor, physicist Gerard O’Neill, who proposed building miles-long, rotating space stations, later dubbed O’Neill cylinders. But if Earth can’t support a trillion people (or even many more billions), how can simulated Earths–made from bits of Earth and whatever we scrounge from asteroids–support even more than our planet? Bezos is used to the exponential growth made possible by Moore’s law–itself bumping against the limits of physics. Life in space will hit those limits far sooner.